Summary: This retrospective cohort study evaluated febrile infants 29-60 days who had a full septic workup and compared rates of meningitis between those with positive versus negative urinalyses. They analyzed 833 infants and found no difference in the percent with meningitis between positive urinalysis (0.9% with meningitis) and negative urinalysis (1.0% with meningitis). An additional 341 infants with positive urinalyses were treated with antibiotics without obtaining a lumbar puncture, and no cases of missed meningitis or adverse outcomes were identified.

Key strengths of the article:A secondary analysis of infants treated for UTI without obtaining CSF found no adverse outcomes. This supplements the primary goal of comparing infants with positive versus negative urinalyses. This study was conducted in a large medical system (Kaiser Permanente), so few patients would be lost to follow up. Finally, the authors used a manual chart review of all records to accurately define clinical data and outcomes.

Key limitations: The authors use a conservative definition of meningitis, which is appropriate to avoid missing cases. However, the 3 cases of meningitis in infants with positive urinalyses had <40 WBC in CSF, two traumatic taps with low growth of bacteria (possibly contamination from blood), and the 3rd case was pre-treated and had no growth. It is possible that none of these 3 cases represented true meningitis. In addition, they comment on clinical predictors of meningitis (ill appearance, decreased urine output, vomiting, higher fever), but would need more patients with meningitis to develop robust positive indicators.

​Major takeaway:This study helps define which febrile infants to classify as high risk. Traditional criteria would classify all febrile infants with a positive urinalysis as high risk, requiring a full septic workup including LP. This study shows that infants 29-60 days with a positive UA are no more likely to have meningitis.

How this article should impact our practice: This article supports the treatment of febrile infants 29-60 days old with UTI without first doing a lumbar puncture. While other lab results or clinical concern may push a physician to obtain CSF, the urinalysis should not be the deciding factor.